In recent years, as functional cosmetics and foods have increasingly drawn attention all over the world, a great deal of studies and investigation into development of improved functional substances using natural plants, animal extracts and the like have been conducted.
Genistein represented by the following formula 1 is one of isoflavones, which are compounds isolated from plants and vegetables, and is well known to exist in soy beans, sophora japonica L., clover and other plants:

Such an isoflavone is typically presented in a glycoside form that has a β-glycoside bonded thereto and/or an aglycone form that does not have a glucose moiety.
Isoflavone glycosides are normally converted into the aglycone form by β-glycosides during digestion thereof. Isoflavone aglycones may include genistein, daidzein, glycitein and the like while isoflavone glycosides may include genistin, diadzein, glyzitin, and so forth.
Especially, isoflavones contained in soy beans may be mostly illustrated by genistin, 6-O-acetyl genistin, 6-O-malonyl genistin, etc., while fruits of sophora japonica L., may contain genistin represented by the following formula 2 as a genistein glycoside and, in addition, a sophoricoside represented by the following formula 3. Likewise, other plants and/or vegetables may contain a variety of genisteins and glycosides thereof.

[Sophoricoside]
In the above formulae 2 and 3, Glu is

A number of animal experiments and human experiments report that genistein exhibits excellent effects of lowering cholesterol levels and inhibiting generation of adipose tissue. It was also disclosed that genistein is effective in protection and treatment of various cancers ROI as breast cancer, prostate cancer, skin cancer, colon cancer and the like, and may reduce or prevent a variety of menopausal symptoms including, for example, osteoporosis. Accordingly, among isolflavones, genistein is the most greatly studied in view of mechanism and safety.
Korean Patent No. 10-0500641 disclosed a hair, composition containing genistein with excellent hair growth promotion effects and/or hair loss prevention effects.
International Patent Application No. PCT/JP2004/006726 also described various applications of an isoflavone composition such as cosmetics, foods, medicines, etc.
Korean Laid-Open Application No. 2005-11889 proposed a transdermal drug composition including genistein for protection of intercellular information delivery performance and, especially, explained skin ageing protection effects of the composition.
Korean Laid-Open Application No. 2007-14672 disclosed a transdermal drug composition containing genistein or daidzein, characterized by inhibiting phagocytosis of dermal keratinocytes and efficiently reducing movement of melanosome from melanocytes into keratinocytes.
Additionally, Korean Laid-Open Application No. 2007-2133 described that a combination of palmitoyl pentapeptide, soy bean germ isoflavone aglycone, alfalfa extract and iris extract improves anti-wrinkle effects and enhances skin resilience.
Isoflavone or genistein mentioned in the above documents often refers to a simple extract directly obtained from soy beans or other plants and/or vegetables. However, it is generally known that isoflavones are minimally soluble in water, thereby inhibiting application thereof to beverages and simple liquid products. Technologies from abroad in regard to water soluble isoflavones have recently been disclosed, including, for example, Japanese Patent No. 10,298,175 and U.S. Pat. No. 5,847,108 owned by FUJICCO Co. Ltd., describing a process for preparation of a water-solubilized isoflavone by an inclusion method using beta-cyclodextrin.
FUJICCO's patents suggested a kneading method including continuous and slow reaction of isoflavone having more than saturation concentration and cyclodextrin in a kneader. However, the process described above requires at least 3 hours for inclusion and a rate of inclusion is not particularly high.
In particular, an inclusion process of a hydrophobic compound may mostly include a simple high agitation process, a process comprising dissolving a compound in an organic solvent and inclusion processing the mixture while evaporating, a kneading method conducted at saturation concentration or more, and the like.
Korean Laid-Open Application No. 2005-39328 describes a process for production of isoflavone from a combination wherein a cyclodextrin solution is added to an isoflavone containing plant to prodire an isoflavone-cyclodextrin combination, followed by extracting isoflavone from the combination using a coagulant.
Japanese Laid-Open Application No. 9-309902 discloses a method for preparation of an inclusion-complex wherein isoflavone and cyclodextrin are dissolved in water, heated and cooled so as to prodire an inclusion-complex which functions to inhibit bitterness.
As described above, there were attempts to conduct inclusion processing of isoflavone by inclusion performance of cyclodextrin. However, these processes have problems such as extended time for inclusion of isoflavone and inferior rate of inclusion.